Fredrick L. Kiechle, MD, PhD
Q. Our emergency department physicians insist on orders for GC Gram stain for female patients. How reliable are GC Gram stains for female patients? Are there recommendations or guidelines for accepting these orders?
A. Gram-stained smears from endocervical specimens collected under direct visualization of the cervix (with a speculum) have a sensitivity of 50 percent to 70 percent, depending on the adequacy of the specimen and the patient population.1 Observing Gram-negative intracellular diplococci in an endocervical smear from a woman with signs and symptoms of gonococcal infection is highly predictive. But specimens can be contaminated with vaginal secretions containing other Gram-negative coccobacilli and bipolar staining bacilli, so Gram-stained smears should not be the only method for diagnosis.
Methods that combine detection for Chlamydia trachomatis as well as Neisseria gonorrhoeae, such as direct probe hybridization, nucleic acid amplification tests, and amplified-signal probe tests, are of greatest value. Culture is still the gold standard for diagnosis of gonococcal infection. The CDC’s recommendations in “Screening Tests to Detect Chlamydia trachomatis and Neisseria gonorrhoeae Infections—2002” say that because of the lower sensitivity of Gram stains of endocervical specimens and the requirement of a skilled microscopist, Gram stains are not recommended.2
The CAP does not have guidelines on accepting these specimens, other than that the personnel who read them out need to be tested for proficiency. Your ED physicians need to be educated about the low sensitivity of the Gram stain for female patients and the possibility of a false-positive, and that nucleic acid detection techniques have a higher sensitivity, can be performed on noninvasive specimens such as urine, and can detect Chlamydia trachomatis as well. Also, for any high-risk patient, a culture should be performed.
1. Murray PR, Baron EJ, Jorgensen JH, et al., eds. Manual of Clinical Microbiology. 9th ed. Washington, DC: ASM Press; 2007.
2. Johnson RE, Newhall WJ, Papp JR, et al. Screening tests to detect Chlamydia trachomatis and Neisseria gonorrhoeae infections—2002. Centers for Disease Control and Prevention. MMWR Recomm Rep. 2002;51(RR15):1–27.
Christina M. Wojewoda, MD
Anatomic and Clinical
Pathology Resident, PGY4
University Hospitals of Cleveland
Member, CAP Microbiology
Q. What are the etiology, diagnostic symptomatology, and therapeutic options for the rare lung anomaly Langerhans cell histiocytosis?
A. Pulmonary Langerhans cell histiocytosis (PLCH), also known as Langerhans granulomatosis or pulmonary eosinophilic granuloma, is an uncommon interstitial lung disease caused by the accumulation of a specific type of histiocyte (Langerhans cell) observed predominantly in adult cigarette smokers. The cigarette smoke is believed to induce activation of Langerhans cells secondary to cytokine production by epithelial cells, resulting in an inflammatory process that leads to formation of lung nodules.
The typical clinical presentation includes nonproductive cough and dyspnea. Less common symptoms are weight loss, fever, fatigue, and pleuritic pain. Recurrent spontaneous pneumothorax may also be the presenting symptom because of the tendency of the disease to form thin-walled cysts within lung parenchyma. The disease can also affect other organs, including skin, lymph nodes, pituitary gland, and bone.
The most important step in managing the disease is smoking cessation, which will often lead to symptom stabilization and radiographic improvement. Some patients may develop progressive disease despite smoking cessation. In such patients, corticosteroids can be used, but they generally offer limited success. Other immunosuppressive agents have been used to treat advanced or progressive PLCH, including vinblastine, cyclophosphamide, methotrexate, and chlorodeoxyadenosine.
Overall, the prognosis for most patients is relatively good, particularly for those who successfully stop smoking. Overall median survival for patients with PLCH is about 13 years. Progressive cases that are refractory to treatment may become candidates for lung trans-plantation.
Vassallo R, Ryu JH. Tobacco smoke-related diffuse lung diseases. Semin Respir Crit Care Med. 2008;29:643–650.
Saul Suster, MD
Professor and Chairman
Department of Pathology
Medical College of Wisconsin
Member, CAP Surgical
Dr. Kiechle is medical director of clinical pathology, Memorial Healthcare, Hollywood, Fla.